fix: Move field_order sync logic to DocType controller and introduce hooks

before_export, before_import and prepare_docdict_for_import

frappe/core/doctype/doctype/doctype.py

@@ -17,7 +17,9 @@ from frappe.desk.notifications import delete_notification_count_for
 from frappe.modules import make_boilerplate, get_doc_path
 from frappe.model.db_schema import validate_column_name, validate_column_length, type_map
 from frappe.model.docfield import supports_translation
+from frappe.modules.import_file import get_file_path
 import frappe.website.render
+import json
 
 # imports - third-party imports
 import pymysql
@@ -390,6 +392,57 @@ class DocType(Document):
 			if naming_series[0].default:
 				make_property_setter(self.name, "naming_series", "default", naming_series[0].default, "Text", validate_fields_for_doctype=False)
 
+	def before_export(self, docdict):
+		# retain order of 'fields' table and change order in 'field_order'
+		docdict["field_order"] = [f.fieldname for f in self.fields]
+
+		path = get_file_path(self.module, "DocType", self.name)
+		if os.path.exists(path):
+			try:
+				with open(path, 'r') as txtfile:
+					olddoc = json.loads(txtfile.read())
+
+				old_field_names = [f['fieldname'] for f in olddoc.get("fields", [])]
+				if old_field_names:
+					new_field_dicts = []
+					remaining_field_names = [f.fieldname for f in self.fields]
+
+					for fieldname in old_field_names:
+						field_dict = filter(lambda d: d['fieldname'] == fieldname, docdict['fields'])
+						if field_dict:
+							new_field_dicts.append(field_dict[0])
+							remaining_field_names.remove(fieldname)
+
+					for fieldname in remaining_field_names:
+						field_dict = filter(lambda d: d['fieldname'] == fieldname, docdict['fields'])
+						new_field_dicts.append(field_dict[0])
+
+					docdict['fields'] = new_field_dicts
+			except ValueError:
+				pass
+
+	@staticmethod
+	def prepare_docdict_for_import(docdict):
+		# set order of fields from field_order
+		if docdict.get("field_order"):
+			new_field_dicts = []
+			remaining_field_names = [f['fieldname'] for f in docdict.get('fields', [])]
+
+			for fieldname in docdict.get('field_order'):
+				field_dict = filter(lambda d: d['fieldname'] == fieldname, docdict.get('fields', []))
+				if field_dict:
+					new_field_dicts.append(field_dict[0])
+					remaining_field_names.remove(fieldname)
+
+			for fieldname in remaining_field_names:
+				field_dict = filter(lambda d: d['fieldname'] == fieldname, docdict.get('fields', []))
+				new_field_dicts.append(field_dict[0])
+
+			docdict['fields'] = new_field_dicts
+
+		if "field_order" in docdict:
+			del docdict["field_order"]
+
 	def export_doc(self):
 		"""Export to standard folder `[module]/doctype/[name]/[name].json`."""
 		from frappe.modules.export_file import export_to_files

frappe/core/doctype/doctype/test_doctype.py

@@ -106,7 +106,7 @@ class TestDocType(unittest.TestCase):
 				if condition:
 					self.assertFalse(re.match(pattern, condition))
 
-	def test_load_file_field_order(self):
+	def test_sync_field_order(self):
 		from frappe.modules.import_file import get_file_path
 		import os
 

frappe/modules/export_file.py

@@ -24,6 +24,7 @@ def export_to_files(record_list=None, record_module=None, verbose=0, create_init
 
 def write_document_file(doc, record_module=None, create_init=True):
 	newdoc = doc.as_dict(no_nulls=True)
+	doc.run_method("before_export", newdoc)
 
 	# strip out default fields from children
 	for df in doc.meta.get_table_fields():
@@ -39,35 +40,7 @@ def write_document_file(doc, record_module=None, create_init=True):
 
 	# write the data file
 	fname = scrub(doc.name)
-	with open(os.path.join(folder, fname + ".json"), 'a+') as txtfile:
-		# if exporting DocType, retain order of 'fields' table and change order in 'field_order'
-		if doc.doctype == "DocType":
-			newdoc["field_order"] = [f.fieldname for f in doc.fields]
-
-			try:
-				olddoc = json.loads(txtfile.read())
-				old_field_names = [f['fieldname'] for f in olddoc.get("fields", [])]
-
-				if old_field_names:
-					new_field_dicts = []
-					remaining_field_names = [f.fieldname for f in doc.fields]
-
-					for fieldname in old_field_names:
-						field_dict = filter(lambda d: d['fieldname'] == fieldname, newdoc['fields'])
-						if field_dict:
-							new_field_dicts.append(field_dict[0])
-							remaining_field_names.remove(fieldname)
-
-					for fieldname in remaining_field_names:
-						field_dict = filter(lambda d: d['fieldname'] == fieldname, newdoc['fields'])
-						new_field_dicts.append(field_dict[0])
-
-					newdoc['fields'] = new_field_dicts
-			except ValueError:
-				pass
-
-		txtfile.seek(0)
-		txtfile.truncate()
+	with open(os.path.join(folder, fname + ".json"), 'w+') as txtfile:
 		txtfile.write(frappe.as_json(newdoc))
 
 def get_module_name(doc):

frappe/modules/import_file.py

@@ -4,8 +4,9 @@
 from __future__ import unicode_literals, print_function
 
 import frappe, os, json
-from frappe.modules import get_module_path, scrub_dt_dn
+from frappe.modules import get_module_path, scrub_dt_dn, load_doctype_module
 from frappe.utils import get_datetime_str
+from frappe.model.base_document import get_controller
 
 ignore_values = {
 	"Report": ["disabled", "prepared_report"],
@@ -89,27 +90,6 @@ def read_doc_from_file(path):
 	else:
 		raise IOError('%s missing' % path)
 
-	# set order of fields from field_order
-	if doc.get("doctype") == "DocType":
-		if doc.get("field_order") and doc.get("fields"):
-			new_field_dicts = []
-			remaining_field_names = [f['fieldname'] for f in doc['fields']]
-
-			for fieldname in doc['field_order']:
-				field_dict = filter(lambda d: d['fieldname'] == fieldname, doc['fields'])
-				if field_dict:
-					new_field_dicts.append(field_dict[0])
-					remaining_field_names.remove(fieldname)
-
-			for fieldname in remaining_field_names:
-				field_dict = filter(lambda d: d['fieldname'] == fieldname, doc['fields'])
-				new_field_dicts.append(field_dict[0])
-
-			doc['fields'] = new_field_dicts
-
-		if "field_order" in doc:
-			del doc['field_order']
-
 	return doc
 
 ignore_doctypes = [""]
@@ -118,8 +98,15 @@ def import_doc(docdict, force=False, data_import=False, pre_process=None,
 		ignore_version=None, reset_permissions=False):
 	frappe.flags.in_import = True
 	docdict["__islocal"] = 1
+
+	controller = get_controller(docdict['doctype'])
+	if controller and hasattr(controller, 'prepare_docdict_for_import') and callable(getattr(controller, 'prepare_docdict_for_import')):
+		controller.prepare_docdict_for_import(docdict)
+
 	doc = frappe.get_doc(docdict)
 
+	doc.run_method("before_import")
+
 	doc.flags.ignore_version = ignore_version
 	if pre_process:
 		pre_process(doc)